Using the inner mounting option will reduce the width of the tire which comes into contact with the ground. This will help to reduce traction roll and will make the overall tire "stiffer."

If you are going to be running on really loose terrain, I'd mount the tires on the outer rings. Just keep in mind that the Badlands aren't particularly meant for racing and they balloon like crazy. I'd try to get a set of the GRP orange foams to minimize this.